Convert Foot to Span
Convert feet to spans instantly. 1 foot = 1.3333333333 span — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Span to Foot converter for the reverse conversion.
Units explained
Foot
A foot is an Imperial and US customary unit of length equal to 12 inches or exactly 0.3048 meters. It is the most commonly used unit of length in everyday measurement in the United States.
The foot's origin is literally the length of a human foot, used as a measurement standard since antiquity. The English foot was standardized at various points in history; the modern international foot (0.3048 m exactly) was fixed by the 1959 International Yard and Pound Agreement.
Feet are used in the US for body height, building dimensions, room sizes, road sign clearances, aviation altitude (feet above sea level), and most everyday distance estimation. The UK uses feet informally for height despite officially being metric.
Used since antiquity; standardized to 0.3048 m exactly by the International Yard and Pound Agreement of 1959. Aviation worldwide uses feet for altitude despite metric adoption elsewhere.
Span
A span is an Imperial unit of length equal to 9 inches (228.6 mm). Historically, it represented the distance from the tip of an extended thumb to the tip of an extended little finger.
The span derives from this natural body-measurement and was standardised at 9 inches in English customary practice.
Spans are rare in modern commerce but appear in historical English literature, biblical translation studies, and reproduction crafts. Some construction and gardening still use 'span' informally.
Ancient body-measure origin; standardised in English customary practice at 9 inches; became exact via the 1959 International Yard and Pound Agreement.
Foot to Span conversion formula
The relationship between feet and spans:
To convert feet to spans, multiply the value in feet by 1.3333333333. To reverse, multiply spans by 0.75.
How to use this converter
Type a value into the calculator. The result in spans updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Span to Foot converter for the reverse direction.
Step-by-step: convert feet to spans
- Write down the value in feet (ft).
- Multiply that value by the factor 1.3333333333.
- The product is the equivalent value in spans (span).
- To reverse, multiply the span value by 0.75.
Worked examples
Example 1 — Convert 1 ft to span:
1 × 1.3333333333 = 1.3333333333 span
Example 2 — Convert 100 ft to span:
100 × 1.3333333333 = 133.3333333333 span
Real-world example — Reference scenario in case of fallback
Conversion between human-scale length units is the everyday workflow of architecture, athletics, and apparel design — three of the most common contexts that span metric and imperial systems.
1 ft × 1.3333333333 = 1.3333333333 span
Real-world example — Adult height conversion
A 1.8-foot-tall person measures a value in spans that converts the height to the unit favoured by American forms, schools, or driver's licences. This is daily routine for anyone living between metric and imperial systems.
1.8 ft × 1.3333333333 = 2.4 span
Real-world example — Fabric purchase length
Two feet of fabric equals a value in spans essential for tailors and textile buyers sourcing material from international suppliers that quote in different units.
2 ft × 1.3333333333 = 2.6666666667 span
Foot to Span conversion table
Standard reference values for converting feet to spans:
| Foot [ft] | Span [span] |
|---|---|
| 0.01 | 0.0133333333 |
| 0.1 | 0.1333333333 |
| 1 | 1.3333333333 |
| 2 | 2.6666666667 |
| 3 | 4 |
| 4 | 5.3333333333 |
| 5 | 6.6666666667 |
| 10 | 13.3333333333 |
| 20 | 26.6666666667 |
| 30 | 40 |
| 40 | 53.3333333333 |
| 50 | 66.6666666667 |
| 100 | 133.3333333333 |
| 500 | 666.6666666667 |
| 1000 | 1333.3333333333 |
Frequently asked questions
How many spans is 1 foot?
How do I convert feet to spans?
How do I convert spans back to feet?
How many spans is 100 feet?
Popular length unit conversions
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Metric / SI (18 units)
Imperial / US Customary (26 units)
Nautical (1 units)
Astronomical (9 units)
Atomic / Physics (6 units)
Typographic (3 units)
Sources & references
Conversion factor (1 ft = 1.3333333333 span) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.